A conventional coin processing machine includes a stationary coin processing plate or rail that supports coins sliding on the plate or rail along a coin path defined on a coin support surface of the plate or rail. A coin slides along the coin path from an initial intake location to a coin removal station where the coin is removed from the support surface. The coin removal station may include, for non-limiting examples, a through-hole that drops coins off the support surface, a guide surface that forces or diverts the coin off the support surface, or a mechanical device that selectively obstructs the coin path and diverts or pushes a coin off the support surface. A coin processing machine may include one coin removal station at the end of the coin path or may include multiple coin removal stations spaced along the coin path. Each station of the multiple removal stations may be dedicated to removing a respective coin denomination off the support surface.
The coins may pass coin sensors, imaging devices, or the like along the coin path to validate and/or determine the diameter and denomination of the coins before reaching the one or more coin removal stations.
A non-limiting example of a known coin processing machine is disclosed in my U.S. Pat. No. 7,243,774, a portion of which is shown in FIG. 8. The coin processing machine includes a conventional processing plate or coin support plate 10, the plate 10 having a flat coin support surface 12. An outer wall 14 extends around a portion of the outer periphery of the support plate 10 and extends above the support plate surface 12. The coin path 16 extends on the support surface 12 adjacent the wall 14 from an upstream intake location represented by the arrow 17 downstream to a coin removal station 18 formed as a through-hole in the plate 10. The coin processing machine is used for coin counting and not coin sorting, and so the coin removal station 18 is the sole coin removal station and removes all the coins from the coin sorting plate.
A sensor set 20 is disposed on the coin path upstream from the coin removal station 18 and determines the size and denomination of coins moving past the sensor set. The radially outermost sensor 20A of the illustrated sensor set 20, for example, is just covered by the outer portion of a US dime moving on the coin path against the wall 14.
Coins are introduced on the coin support surface 12 at the intake location 17 and slide along the coin path 16 to the coin removal station 18. A rotating drive member located above the processing plate has circumferentially spaced, radially elongate, resilient fingers 22 that extend down and press the coins against the support surface 12, the fingers engaging and driving the coins on the coin path 16 (for clarity, only one finger 22 is shown in phantom lines in FIG. 4). The fingers 22 apply a drive torque or a drive force urging the coins along the coin path, but enable centrifugal force to urge the coins against the wall 14 to accurately position the coins on the coin path 16. This feature is conventional and so will not be described in greater detail.
When wet coins are fed onto the coin support surface 12, a wet coin occasionally becomes stationary on the coin support surface 12 and is unable to be driven by the drive member. It is theorized that moisture generates “suction” causing drag between the coin and the coin support surface 12. The drive member is unable to overcome the drag and the coin comes to a stop, creating a jam in the coin processing machine. The drive member continues attempting to move the stationary coin but cannot. The machine must be stopped to clear the coin jam.
The current series of US dime has a diameter of 17.91 mm and a thickness of 1.35 mm and is the thinnest and lightest US coin denomination. Because of this, a wet dime is by far the most likely coin to become stationary on the coin support surface. Being the thinnest coin, the force applied to dimes by the drive member is lower than other coins. It is therefore more difficult for the drive member to apply force sufficient to overcome the drag applied to the dime by moisture.
It would be desirable to reduce the tendency of wet coins to stop on the processing plate. It would also be desirable to automatically stop the drive member when a coin jam occurs on the processing plate of the coin processing machine.